1. Field
Embodiments described herein relate to a mask manufacturing method, and a semiconductor device manufacturing method.
2. Description of the Related Art
Recently, along with advancement of downsizing of semiconductor devices, a problem in a photolithography step in the semiconductor device manufacturing process has become remarkable. Concretely, in a design rule of the latest semiconductor device at this point, downsizing has so advanced that the half pitch (hp) is about 22 nanometers, and when the conventional lithography by a reduced pattern transcription using light is used, resolution of this order cannot be achieved, resulting in a situation where the pattern formation has become difficult. As a result, in recent years, instead of the lithography, nanoimprint technique has been employed.
The nanoimprinting is a technique for forming a pattern on a substrate. Concretely, the nanoimprinting includes pressing an imprint mask having a pattern shape formed thereon against an imprint material (a coating material) coated on the substrate, waiting until the imprint material solidifies thereby forming a model of the pattern shape on the imprint mask. The nanoimprinting is free of variable factors such as a focal depth, aberration, and an exposure amount that caused problem in the conventional lithography that employed light. Moreover, if only a highly accurate imprint mask is formed, it is possible to very easily and accurately transcript the pattern of the imprint mask.
Meanwhile, when manufacturing semiconductor devices, a new pattern is sometimes formed on a substrate having an old pattern previously formed thereon. When the nanoimprint technique is used to form such a new pattern, high alignment accuracy is required between the imprint mask and the substrate. A pattern on the imprint mask generally has positional distortion, so that when forming a new pattern that matches with an underlying old pattern, it is preferable to first solve the issue of pattern positional distortion of the imprint mask. With respect to a first-order component deviation such as a magnification, for example, out of the pattern positional distortion, the deviation can be taken care of by pressing an end surface of the imprint mask. Such a technique has been disclosed, for example, in D. L. White and O. R. Wood II, “Novel alignment system for imprint lithography”, The Journal of Vacuum Society Technology B 18(6), November/December 2000, American Vacuum Society. However, when the imprint mask has a pattern positional deviation of a second or higher order complicated shape, or when the magnification needs to be enlarged, for example, there is a problem that with the method described in the above-mentioned literature, it is not possible to solve the pattern positional distortion of the imprint mask.